Process for the production of esterquats

ABSTRACT

Esterquats based on natural fats and oils can be directly produced by subjecting fatty acid glyerine ester to ester interchange, in the presence of alkaline and/or alkaline earth boron hydrides and hypophosphoric acid or their alkaline and/or alkaline earth salts and possibly free fatty acid, with hydroxy-functionalised tertiary amines and quaternising the resultant products in the manner known per se.

This application is a 371 of PCT/EP 95/00861 filed May 9, 1995.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a process for the production of esterquats, inwhich fatty acid glycerol esters are directly transesterified withtertiary hydroxyamines and then quaternized, and to the use of theproducts for the production of surface-active formulations.

2. Statement of Related Art

In recent years, quaternized fatty acid triethanolamine ester salts,socalled "esterquats", have acquired increasing significance asecotoxicologically safe raw materials for fabric softeners cf. O.Ponsati in C.R. CED Congress, Barcelona, 167 (1992) and R. Puchta inC.R. CED Congress, Sitges, 59 (1993)!.

According to the teaching of International patent application WO91/01295 (Henkel), esterquats are normally produced from triethanolamineor adducts of ethylene oxide with triethanolamine which, in a firststep, are partly esterified with linear C_(16/18) fatty acids in thepresence of hypophosphorous acid and subsequently treated with air. Thefatty acid triethanolamine esters are then quaternized, for example withalkyl halides or, preferably, dialkyl sulfates.

Instead of fatty acids themselves, it is desirable for economic reasonsdirectly to use natural fats and oils, from which the fatty acids areobtained, as starting materials for the production of esterquats.However, according to studies conducted by applicants, application ofthis principle on an industrial scale has hitherto been prevented by thefact that transesterification in the presence of the alkaline catalyststypically used for this type of reaction, namely potassium hydroxide orsodium methylate, generally involves overly long reactor possessiontimes and, in general, leads to discolored products which have to bebleached in an additional, expensive process step.

Accordingly, the problem addressed by the present invention was toprovide a process for the production of esterquats based on fats andoils as starting materials which would not have any of the disadvantagesmentioned above.

DESCRIPTION OF THE INVENTION

The present invention relates to a process for the production ofesterquats in which fatty acid glycerol esters are subjected totransesterification with hydroxyfunctionalized tertiary amines in thepresence of alkali metal and/or alkaline earth metal borohydrides andhypophosphorous acid or alkali metal and/or alkaline earth metal saltsthereof and, optionally, free fatty acid and the resulting products arequaternized in known manner.

It has surprisingly been found that the use of borohydrides as opposedto other conventional transesterification catalysts leads to a quick andcomplete reaction which, in addition, gives reaction products that aredistinguished by particularly high color quality. In addition, theprocess according to the invention affords the advantage that fats andoils can be directly used instead of fatty acids which increases theeconomy of the process.

Esterquats

Esterquats are generally understood to be quaternized fatty acidtriethanolamine ester salts. These are known substances which may beobtained by the relevant methods of preparative organic chemistry, cf.International patent application WO 91/01295 (Henkel). According to thisdocument, triethanolamine is partly esterified with fatty acids in thepresence of hypophosphorous acid, air is passed through and the fattyacid triethanolamine esters are subsequently quaternized with dimethylsulfate or ethylene oxide. U.S. Pat. No. 3,915,867, U.S. Pat. No.4,370,272, EP-A2 0 239 910, EP-A2 0 293 955, EP-A2 0 295 739 and EP-A2 0309 052 are cited at this juncture as representative of the extensiveprior art on this subject.

The quaternized fatty acid triethanolamine ester salts correspond toformula (I): ##STR1## in which R¹ CO is an acyl radical containing 6 to22 carbon atoms, R² and R³ independently of one another representhydrogen or have the same meaning as R¹ CO, R⁴ is an alkyl radicalcontaining 1 to 4 carbon atoms or a (CH₂ --CH₂ O)_(q) H group, m, n andp have a combined value of 0 or 1 to 12, q is a number of 1 to 12 and Xis halide, alkyl sulfate or alkyl phosphate.

Typical examples of esterquats which may be used in accordance with theinvention are products based on caproic acid, caprylic acid, capricacid, lauric acid, myristic acid, palmitic acid, isostearic acid,stearic acid, oleic acid, elaidic acid, arachic acid, behenic acid anderucic acid and the technical mixtures thereof obtained, for example, inthe pressure hydrolysis of natural fats and oils. Technical C_(12/18)cocofatty acids and, in particular, partially hydrogenated C_(16/18)tallow or palm oil fatty acid and also C_(16/18) fatty acid cuts rich inelaidic acid are preferably used.

Quaternized fatty acid triethanolamine ester salts corresponding toformula (I), in which R¹ CO is an acyl radical containing 16 to 18carbon atoms, R² has the same meaning as R¹ CO, R³ is hydrogen, R⁴ is amethyl group, m, n and p have a combined value of 0 and X stands formethyl sulfate, have proved to be particularly advantageous from theperformance point of view.

Besides the quaternized fatty acid triethanolamine ester salts, othersuitable esterquats are quaternized ester salts of fatty acids withdiethanol alkylamines corresponding to formula (II): ##STR2## in whichR¹ CO is an acyl radical containing 6 to 22 carbon atoms, R² is hydrogenor has the same meaning as R¹ CO, R⁴ and R⁵ independently of one anotherrepresent alkyl radicals containing 1 to 4 carbon atoms, m and n have acombined value of 0 or 1 to 12 and X stands for halide, alkyl sulfate oralkyl phosphate.

Finally, another group of suitable esterquats are the quaternized estersalts of fatty acids with 1,2-dihydroxypropyl dialkylaminescorresponding to formula (III): ##STR3## in which R¹ CO is an acylradical containing 6 to 22 carbon atoms, R² is hydrogen or has the samemeaning as R¹ CO, R⁴, Re and R⁷ independently of one another representalkyl radicals containing 1 to 4 carbon atoms, m and n have a combinedvalue of 0 or 1 to 12 and X stands for halide, alkyl sulfate or alkylphosphate.

So far as the choice of preferred fatty acids is concerned, the examplesmentioned for (I) also apply to the esterquats of formulae (II) and(III).

Fatty acid glycerol esters

Fatty acid glycerol esters in the context of the invention are syntheticor preferably natural triglycerides, diglycerides, monoglycerides ortechnical mixtures thereof. The glycerol esters generally contain fattyacids with 6 to 22 and preferably 12 to 18 carbon atoms. They may besaturated or may contain up to 3 double bonds. In addition, the glycerolesters may contain one type of fatty acid or up to three different fattyacids. Typical examples of triglycerides which may be used in theprocess according to the invention are palm oil, palm kernel oil,coconut oil, olive oil, rapeseed oil from old and new plants, sunfloweroil from old and new plants, cottonseed oil, linseed oil, peanut oil,beef tallow and lard. From the performance point of view, it ispreferred to use completely or partly hydrogenated beef tallow or palmoil with iodine values in the range from 0 to about 50.

Hydroxyfunctionalized tertiary amines

In the transesterification reaction, at least one fatty acid of theglyceride reacts with one OH group of a hydroxyfunctionalized tertiaryamine. Typical examples of suitable amines are diethanol alkylaminessuch as, for example, diethanol methylamine and 1,2-dihydroxypropyldialkylamines such as, for example, 1,2-dihydroxypropyl dimethylamineand, in particular, triethanolamine.

The fatty acid glycerol esters--expressed on the basis of the fattyacids present in them--and the amines may be used in a molar ratio ofaround 1.2:1 to 2.2:1 and preferably 1.4:1 to 1.9:1.

Catalysts

Alkali metal and/or alkaline earth metal borohydrides may be used as thetransesterification catalysts. Typical examples are potassium ormagnesium borohydride and preferably sodium borohydride. The catalystsare normally used in quantities of 50 to 1000

ppm and preferably in quantities of 100 to 500 ppm, based on theglycerol ester.

Suitable co-catalysts are hypophosphorous acid and alkali metal and/oralkaline earth metal salts thereof, preferably sodium hypophosphite,used in quantities of 0.01 to 0.1% by weight and preferably inquantities of 0.05 to 0.07% by weight, based on the glycerol ester.

Fatty acids

In one preferred embodiment of the process according to the invention,the transesterification reaction takes place in the presence of freefatty acids containing 6 to 22 and preferably 12 to 18 carbon atomswhich may be used in quantities of 1 to 5% by weight and, moreparticularly, 2 to 3% by weight, based on the glycerol ester. Typicalexamples of suitable fatty acids are caproic acid, caprylic acid,2-ethylhexanoic acid, capric acid, lauric acid, isotridecanoic acid,myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearicacid, oleic acid, elaidic acid, petroselic acid, linoleic acid,linolenic acid, elaeostearic acid, arachic acid, gadoleic acid, behenicacid and erucic acid and the technical mixtures thereof obtained, forexample, in the pressure hydrolysis of natural fats and oils or in thereduction of aldehydes from Roelen's oxosynthesis.

Technical fatty acids containing 12 to 18 carbon atoms, for examplecoconut oil, palm oil, palm kernel oil or tallow fatty acid, whichcorrespond to the fatty acid of the triglyceride used are preferred.

Transesterification

The transesterification is normally carried out over a period of 1 to 12hours and preferably 3 to 6 hours at temperatures in the range from 160°to 240° C. and preferably at temperatures in the range from 180° to 220°C.

Quaternization

The fatty acid hydroxyalkylamine esters and the quaternizing agents maybe used in a molar ratio of 1:0.95 to 1:1.2 and preferably in a molarratio of 1:1 to 1:1.1 in the quaternization reaction. Suitablealkylating agents are alkyl halides, for example methyl chloride,dialkyl sulfates, for example dimethyl sulfate, dialkyl phosphates anddialkyl carbonates, for example dimethyl carbonate or diethyl carbonate.The reaction usually takes place in a solvent, for example a loweralcohol (isopropyl alcohol), a fatty alcohol (ceteareth alcohol), anonionic surfactant (alkyl oligoglucoside, adducts of ethylene oxidewith fatty alcohols or partial glycerides) or a hydroxycarboxylic acid(glycolic acid). The quaternization is preferably carried out attemperatures of 70° to 100° C. and, more particularly, at temperaturesof 80° to 90° C. The reaction time may be between 1 and 24 h and ispreferably between 2 and 8 h. After the quaternization, it is advisableto destroy unreacted alkylating agent by addition of ammonia, glycine ormonoethanolamine.

Commercial Applications

The esterquats obtainable by the process according to the invention aredistinguished by excellent fabric-softening and antistatic properties.

Accordingly, the present invention also relates to their use for theproduction of fabric softeners and hair-care formulations, such assofteners for textiles, yarns and fibers, household fabric softeners,hair shampoos, hair conditioners, hair rinses and the like, in whichthey may be present in quantities of 1 to 30% by weight and preferablyin quantities of 5 to 15% by weight, based on the particularformulation.

The following Examples are intended to illustrate the invention withoutlimiting it in any way.

EXAMPLES

General production procedure

a) Esterification. 0.4 to 0.63 mole of triglyceride (corresponding to1.2 to 1.9 mole, based on fatty acid), 149 g (1 mole) oftriethanolamine, 0.05% by weight of sodium hypophosphite, 100 to 500 ppmof catalyst and, optionally, 2.7% by weight of tallow fatty acid (allpercentages by weight based on the triglyceride) were introduced into a1 liter three-necked flask equipped with a stirrer, internal thermometerand distillation head. The reaction mixture was heated for 5 h to atemperature of 220° C. The crude tallow fatty acid triethanolamine esterwas then cooled, the reactor was vented and 1 liter of air was passedthrough over a period of 15 minutes with continuous stirring.

The results of the esterification tests are set out in Table 1.

b) Quatemization. In a 1.5 liter glass autoclave equipped with a stirrerand internal thermometer, 63 g (0.5 mole) of dimethyl sulfate were addedto 0.5 mole of the ester according to a) in 150 ml of isopropyl alcohol.The reaction mixture was stirred for 2 h at 90° C. and, after cooling,the reactor was vented. To destroy traces of unreacted alkylating agent,2 g of glycine were then added to the reaction mixture, followed bystirring for 1 h at 60° C.

                  TABLE 1    ______________________________________    Transesterification of Triglycerides                             c (Cat)                                    c (FA)  t    Color    Ex.  E     R       Cat   ppm    % by weight                                            h    Gardner    ______________________________________    1    A     1.2:1   NaBH.sub.4                             100    2.7     4    1.0    2    A     1.6:1   NaBH.sub.4                             100    2.7     4    1.2    3    A     1.9:1   NaBH.sub.4                             100    2.7     4    1.5    4    A     1.9:1   NaBH.sub.4                             500    2.7     4    1.0    5    A     1.9:1   NaBH.sub.4                             100    --      4    1.5    6    B     1.9:1   NaBH.sub.4                             100    2.7     4    1.5    7    C     1.9:1   NaBH.sub.4                             100    2.7     4    1.5    C1   A     1.9:1   KOH   100    2.7     6    3.5    C2   A     1.9:1   NaOMe 100    2.7     7    3.5    ______________________________________     Legend:     E = Educt     A = Hydrogenated beef tallow     B = Partly hydrogenated beef tallow     C = Palm oil     R = Ratio of fatty acid (in the triglyceride) to triethanolamine     Cat = Catalyst     FA = Fatty acid (corresponding to the triglyceride)     c = Concentration     t = Time required to establish an acid value < 5

What is claimed is:
 1. A process for producing an esterquat comprisingthe steps of: ( 1) reacting a fatty acid glycerol ester and ahydroxyfunctionalized tertiary amine in the presence of a catalystselected from the group consisting of an alkali metal borohydride, analkaline earth metal borohydride, and a combination thereof; (2)reacting the product of step (1) with a quaternizing agent.
 2. Theprocess of claim 1 wherein said esterquat is a compound of the formula(I): ##STR4## wherein R¹ CO is an acyl radical having from 6 to about 22carbon atoms, each of R² and R³ is hydrogen or R¹ CO as defined above,R⁴ is an alkyl radical having from 1 to 4 carbon atoms or a (CH₂ CH₂O)_(q) H group; wherein m, n and p are numbers having a sum of from 0 to12; q is a number from 1 to 12 and X is a halide, an alkyl sulfate or analkyl phosphate anion.
 3. The process of claim 1 wherein said esterquatis a compound of the formula (II): ##STR5## wherein R¹ CO is an acylradical having from 6 to about 22 carbon atoms, R² is hydrogen or R¹ COas defined above, each of R⁴ and R⁵ is an alkyl radical having from 1 to4 carbon atoms, m and n are numbers having a sum of from 0 to 12 and Xis a halide, an alkyl sulfate or an alkyl phosphate anion.
 4. Theprocess of claim 1 wherein said esterquat is a compound of the formula(III) ##STR6## wherein R¹ CO is an acyl radical having from 6 to about22 carbon atoms, R² is hydrogen or R¹ CO as defined above, each of R⁴,R⁶ and R⁷ is an alkyl radical having from 1 to 4 carbon atoms, m and nare numbers having a sum of from 0 to 12 and X is a halide, an alkylsulfate or an alkyl phosphate anion.
 5. The process of claim 1 whereinsaid fatty acid glycerol ester is a triglyceride, a diglyceride, amonoglyceride or technical mixture thereof.
 6. The process of claim 1wherein said fatty acid glycerol ester is a completely or partlyhydrogenated beef tallow, a palm oil having an iodine value of 0 toabout
 50. 7. The process of claim 1 wherein said hydroxyfunctionalizedtertiary amine is triethanolamine, diethanol alkylamine,1,2-dihydroxypropyl dialkylamine or a combination thereof.
 8. Theprocess of claim 1 wherein the molar ratio of amine to fatty acid insaid fatty acid glycerol ester is from about 1.2:1 to about 2.2:1. 9.The process of claim 1 wherein said catalyst is sodium borohydride. 10.The process of claim 1 wherein the amount of said catalyst is from about50 to about 1000 ppm by weight of said glycerol ester.
 11. The processof claim 1 wherein the amount of said catalyst is from about 0.01 toabout 0.1% by weight of said glycerol ester.
 12. The process of claim 1wherein the amount of said catalyst is from about 1% to about 5% byweight of said glycerol ester.
 13. The process of claim 1 wherein step(1) is carried out over a period of from about 1 to about 12 hours at atemperature of from about 120° to about 180° C.
 14. The process of claim1 wherein said quaternizing agent is an alkyl halide, a dialkyl sulfate,a dialkyl phosphate and a dialkyl carbonate.